physiology Flashcards
what occurs when local electrical change triggers a wave of excitation that travels along the muscle fiber
conductivity
what is the capability of being stretched between contractions
extensibility
how does muscle attach to bone
via tendons
what is connective tissue around muscle cells
endomysium
what is connective tissue around muscle fascicles
perimysium
what is connective tissue surrounding entire muscle
epimysium
where does regulation of calcium for muscle fibers occur
sarcoplasmic reticulum
what is the plasma membrane of a muscle fiber
sarcolemma
what is the cytoplasm of a muscle fiber
sarcoplasm
what is the filamentous proteins which provide structure and contractile capacity to muscle
myofilaments
what are large intracellular bundles of contractile protein myofilaments
myofibrils
what are the tubular invaginations of the sarcolemma which penetrate through the cell and emerge on the other side; essential for calcium release from cisternae
transverse tubules
what is the thick filament primary made of
myosin
what is the thin filament mostly made of
actin
describe the protein of myosin
it is a hexametric protein, composed of 2 heavy chain polypeptides and 4 light-chain polypeptides
what are the 3 functions of the myosin sub fragment-1(S-1)
attachment site for actin to form actomyosin linkages (cross bridges), binding site for adenosine nucleotides, ATPase enzymatic region for hydrolysis of ATP
what is actomyosin complex formation triggered by
calcium
what filaments are in the H band
thick
what filaments are in the I band
thin
what is the segment of the myofibril from one z disc to the next
sarcomere
what is the functional contractile unit of the muscle fiber
sarcomere
what type of potential occurs in the cell body
local potential (has to do with chemical release)
how many neurons is each somatic motor fiber innervated by
one motor neuron
how many fibers does one alpha motor neuron have
typically many
are alpha motor neurons typically associated with extrafusal or intrafusal fibers
extrafusal fibers
are gamma motor neurons typically associated with
intrafusal
what is the average motor unit
200 muscle fibers for each motor unit
what type of fibers does the muscle spindle receptor have
1a
what type of fibers does the golgi tendon organ have
1b
what type of receptors does the free nerve endings have
3 or 4
what type of receptors are nuclear chain fibers most associated with
steady-state (tonic) receptors
what type of receptors are nuclear bag fibers most associated with
adapting (phasic;dynamic) receptors
what is the function of muscle spindles
to inform the CNS of muscle length and dynamic movements
what part of intrafusal fibers cannot contract
the middle of the fiber because it lacks sarcomeres
what is another name for the primary afferent neuron
group 1a
what is another name for the secondary afferent neuron
group 2
where do gamma motoneurons originate
in the anterior horn of the spinal cord
what is the stretch reflex primarily mediated by
the brain
what type of reflex is the golgi tendon organ
clasp knife
what type of fibers does the golgi tendon organ have
1b
